The goal of developing a biotherapeutic that is safe and efficacious and receives regulatory approval with few hurdles is beset with challenges. Management of interfering drug in the ADA assay is clearly a common difficulty, together with the timing and
protocol for neutralizing antibody assays, and the clinical significance of all immunogenicity assays, particularly in the presence of pre-existing drug. CHI's Eighth Annual Immunogenicity Assessment & Clinical Relevance conference
presents approaches from leading Pharma and Biotech and from the clinic for a wide range of products: enzyme replacement therapies, multi-domain antibody products, ADCs, Pegylated biotherapeutics, Botulinum neurotoxins and anti-TNF monoclonal antibodies.
The FDA and NDA Advisory Board will present the regulatory perspectives for innovators and biosimilars.

The cost to the biotechnology industry of developing a biologic from early stage all the way to licensing is very high, and many factors can impinge upon approval, particularly the occurrence of immune responses against the biologic. Immunogenicity can
impact product efficacy and safety depending on patient-related and product-related factors. This presentation will provide an updated overview of the FDA regulatory perspective to immunogenicity risk management for innovator and biosimilar biologics
including risk assessment and mitigation, and anti-drug antibody detection.

9:05 Challenges in Assessing Relative Immunogenicity for Biosimilars and for Manufacturing Change

Paul Chamberlain, NDA Advisory Board

This presentation will reflect on how the extent of the evaluation of relative immunogenicity of closely related therapeutic proteins is strongly dependent on the nature of the product and the regulatory purpose. Directly comparative clinical evaluation
is normally required for biosimilars, whereas a requirement for clinical data is exceptional in the case of manufacturing process changes for authorized products. The importance of minimization of bioanalytical bias, sensitivity of the clinical population,
and duration of interventional monitoring for building an effective strategy will be highlighted.

As biopharmaceuticals revolutionize patient care, safety issues may arise through drug/anti-drug antibody interactions. How do we ensure that immunogenicity testing post licensing in routine clinical practice is standardized and fit for purpose? Although
there is no “perfect” ADA assay, can universal standards be implemented in the ADA sphere? This presentation will focus on newly developed approaches to use reference standards in the assessment of immunogenicity.

There is no finalized guidance from the US Food and Drug Administration (FDA) to govern the validation and use of assays to detect anti-drug antibodies (ADA). To date, investigators have relied on consensus industry white papers for direction
on best practices. The absence of finalized guidance leaves the industry at risk from a complete lack of understanding of the FDAs standing on critical areas of assay design and interpretation. The FDA released a draft Guidance Document
in April 2016, which provides some clarity around requirements and recommended approaches to implement ADA methods. In this talk we will review the recommendations of the new draft guidance and discuss how to address any challenges to
compliance that might be foreseen.

Antibody Drug Conjugates (ADCs) are a new class of anti-cancer medicines consisting of a tumor-specific antibody, a cytotoxic toxin, and a linker. Each of these components either by itself or in combination with the others can induce immune responses
in patients including generation of antibodies (NAbs) capable of neutralizing the therapeutic effects of the ADC. This presentation will describe technical challenges and potential solutions in development of NAb assays for ADCs.

I will describe a novel method that is effective at solving interference problems in immunogenicity assays. I will outline the principles behind the Precipitation and Acid (PandA) approach developed by Sanofi for detecting free and drug-bound
ADA in the presence of high levels of circulating drug and drug target in patient samples. Case studies demonstrating superiority over other methods will be presented.

Drug intolerance in ADA assays remains a significant bioanalytical challenge as it interferes with the proper assessment of immunogenicity. This presentation is aimed at providing practical approaches to reducing drug interference in ADA assays.
Case studies where changes to either assay format or platform as well as specific examples in which simple modifications to assay parameters and reagents resulted in ten-fold or higher increase in drug tolerance will be presented.

3:20 Refreshment Break in the Exhibit Hall with Poster Viewing

4:00 Method to Improve the Recovery of pH Labile Anti-Drug Antibodies during Acid Dissociation and Extraction

When large amounts of biotherapeutic drug are present in clinical samples, these drugs have to be dissociated and removed from anti-drug antibodies (ADA) so that ADAs can be detected by either ligand-binding assays or cell-based bioassays.
By screening a panel of more than 20 ADA positive control (PC) Abs, we found that the current widely used acid dissociation method followed by biotinylated-drug extraction led to low recovery of more than 40% of these ADA PCs, due
to sensitivity to low pH and denaturation. Here we discuss the alternative methods for ADA extraction so that pH labile species can be maximally recovered. This will increase the sensitivity of immunogenicity testing.

Assessment of immunogenicity is increasingly becoming the standard of care for patients being treated with monoclonal antibody therapeutics, particularly for evaluation of loss of response. However, a significant challenge is the potential
for drug target interference. In this session, methods for assessment of anti-drug antibodies to adalimumab and infliximab will be discussed, with a focus on the analytical impact and clinical relevance of drug target interference.

Pre-Existing Antibodies

8:35 Determination of the Clinical Significance of Pre-Existing Antibodies

Therapeutic reactive pre-existing antibodies have been widely detected during clinical immunogenicity evaluation and have received growing attention in the past decade. The related clinical significance ranges from severe adverse
safety findings to no impact at all. This talk will provide an overview of the known clinical impact of pre-existing antibodies and discuss the clinical risk assessment and management strategies.

Case Studies

9:05 FEATURED PRESENTATION: Relationship between Immunogenicity, Drug Concentration, Efficacy, Safety and How this Correlates with Tests/Methods for TNF Inhibitors

Boris Gorovits, Ph.D., Senior Director, PDM, Pfizer, Inc.

This presentation will focus on reported immunogenicity data for anti-TNF mAb and similar compounds with the goal to link with PK, efficacy and other clinical observations. Also, to understand whether the methods applied to evaluate
immunogenicity responses had any influence on the outcome of the correlation to determine relevance of immunogenicity assays.

This talk will describe the ongoing immunogenicity risk assessment, strategic planning and bioanalytical assay development to support a novel biotherapeutic containing multiple effector domains each with an endogenous counterpart.
In addition to the need to closely monitor anti-drug antibody responses due to the potential cross reactivity against the endogenous counterparts, the biotherapeutic also has soluble targets that have the possibility of generating
false positives in screening ADA assays using the bridging format. The goal will be to present the case for early assessment of immunogenicity risk to drive the generation of the numerous reagents and associated procedures
to support the clinical development of this molecule.

To support the clinical development of benralizumab (a humanized anti-IL5Rα mAb with enhanced (afucosylation) antibody-dependent cell-mediated cytotoxicity (ADCC) function, we developed NAb assays in two platforms, ligand-binding
assay and ADCC cell-based assay. We validated both assays and compared them for suitability and practicality to detect NAbs in human serum samples. Our data demonstrated advantages of ligand-binding NAb assay in different aspects
and supported the choice of a ligand-binding NAb assay for the pivotal trials.

Anti-drug antibodies (ADA) can impair the treatment effect of biologics and have been associated with adverse events. However, it is important to distinguish transient from persistent ADA and how this covariate (continuous or categorical)
is included in pharmacological models. ADA are typically used in a reactive setting to support treatment decisions, whereas drug concentrations can be used in a proactive setting to guide dosing based on exposure.

A FVIIa analogue with 3 amino acid mutations compared to the native molecule was developed to improve the treatment of bleeds in hemophilia patients. In the Phase III trial, 8/72 (11%) of the treated patients developed anti-drug
antibodies (ADAs). The presentation will describe the characterisation and consequences of these ADAs. Furthermore, data from a 3 year follow-up study of the ADA positive patients will be presented.